Showing papers by "Voronezh State University published in 2020"

"Flora of Russia" on iNaturalist: a dataset.

Abstract: Background The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people were involved in the data collection. New information Within 20 months, the participants accumulated 750,143 photo observations of 6,857 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 87% of all project data, i.e. 652,285 observations, are available under free licences (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities.

Inventing Nostalgia for the “Golden Age” of the National Middle Ages and Fear of the Future

Abstract: The author analyses features and trends within the development of medievalism and futurism in Japanese mass culture. Mass culture in Japan arose as one of many consequences of political, social and cultural modernization. Medievalism and futurism simplify ideas regarding the past or the future (futurism) and incorporate their elements into the mass culture. These cultural phenomena are analyzed in the context of the imagination of communities, the invention of traditions, and the simulation of classical heritage within a Japanese context. The author analyses cultural situations in which the intellectual discourse of mass culture develops along ethnic lines, while also acknowledging the contribution of modern technological civilization. Medievalism in the identity of modern Japanese mass culture actualizes the myth of the ethnographic "golden age" of medieval culture’s feudal daimyo and samurai sub-culture. By contrast, futurism actualizes cultural phobias that are inspired by feelings of insecurity about the future of civilization. It is assumed that medievalism and futurism as forms of cultural escapism in Japanese popular culture arose as a consequence of the trauma of forced de-archaisation and de-feudalization, forced military and economic modernization, and the miraculous success of Japan’s economic growth and expansion in the post-war era. The author believes that these factors actualized social discomfort and stimulated escapist practices. The author analyses these phenomena within the context of mass culture, believing that a consumer society requires reflection upon the national past in order to yield a visualization of its continuity with earlier social institutions.

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces.

Abstract: The mechanism features of colloidal quantum dots (QDs) passivation with thioglycolic acid molecules (TGA) for cases of different luminescent properties is considered using FTIR. This problem is considered based on FTIR spectra analysis for various ionic forms of TGA. Experimental TGA molecules FTIR spectra is interpreted, basing on the data on modeling of TGA vibrational modes, realized in the framework of density functional method (DFT /B3LYP/6-31+G(d)) taking into account the vibrations anharmonicity of every functional group. This approach provides a significant improvement in the agreement between the experimental and calculated data. FTIR spectra of Ag 2 S/TGA QDs with exciton and recombination luminescence are differ from each other and B “freeB” TGA molecules. The ν ( S − H ) TGA peak (2559 cm − 1 ) disappears in FTIR spectra of Ag 2 S/TGA QD samples. This fact indicates the interactions between TGA thiol group and dangling bonds of Ag 2 S nanocrystals. Ag 2 S QDs passivation with TGA molecules leads to emergence ν a s (COO − ) (1584 cm − 1 ) and ν s (COO − ) (1387 cm − 1 ) peaks. It indicates TGA adsorption in ionic form. For Ag 2 S/TGA QDs with exciton luminescence we observed (a) significant low-frequency shift of ν s (COO − ) peak from 1388 cm − 1 to 1359 cm − 1 and high-frequency shift of ν a s (COO − ) peak from 1567 cm − 1 to 1581 cm − 1 ; (b) change in the ratio of intensities of ν a s (COO − ) and ν s (COO − ) vibrations. This feature is caused by the change in the symmetry of TGA molecules due to passivation of Ag 2 S quantum dots.For Ag 2 S/TGA QDs with recombination luminescence, the insignificant high-frequency shift of 7–10 cm − 1 for ν a s (COO − ) at 1567 cm − 1 and low-frequency shift of 3–5 cm − 1 for ν s (COO − ) at 1388 cm − 1 , probably caused by the interaction of thiol with Ag 2 S surface is observed. Using FTIR spectra, it was found that IR luminescence photodegradation is also accompanied by changes in the thioglycolic acid molecules, which capped Ag 2 S QDs. In the case of Ag 2 S QDs with exciton luminescence, the degradation process is non-reversible. It is accompanied by TGA photodegradation with the formation of α -thiol-substituted acyl radical (S-CH 2 -CO • ) TGA.

High-order harmonic generation during different overlaps of two-colored pulses in laser-produced plasmas and gases

Abstract: In high-order harmonic generation in low-dense media, the application of two-colored pump has been shown to enhance odd-order harmonics, as well as the generation of strong even harmonics. Here, we apply this approach to compare high-order harmonic generation from laser-produced plasmas and gases using different mechanisms of harmonic emission enhancement. We generate two-color pump (TCP, 806 nm + 403 nm and 1030 nm + 515 nm) using two nonlinear crystals of different thickness (0.2 and 0.4 mm in the case of experiments with plasmas using 806 nm pump; and 0.1 mm and 0.4 mm in the case of experiments with gases and plasmas using 1030 nm pump) to demonstrate the enhancement of odd and even harmonics in laser-produced plasmas and by applying weak second field (403 or 515 nm) at different overlaps of pump pulses. The high-order harmonic generation in two media using TCP pulses is optimized. We demonstrate the wavelength dependence and the prevailing role of the partial overlap between the two orthogonally polarized waves in laser-produced plasmas and gases over large ratios of the second-order and fundamental photons. Our results are supported by the non-perturbative single atom theory and the interference model simulations.

p62-Nrf2-p62 Mitophagy Regulatory Loop as a Target for Preventive Therapy of Neurodegenerative Diseases

Abstract: Turnover of the mitochondrial pool due to coordinated processes of mitochondrial biogenesis and mitophagy is an important process in maintaining mitochondrial stability. An important role in this process is played by the Nrf2/ARE signaling pathway, which is involved in the regulation of the expression of genes responsible for oxidative stress protection, regulation of mitochondrial biogenesis, and mitophagy. The p62 protein is a multifunctional cytoplasmic protein that functions as a selective mitophagy receptor for the degradation of ubiquitinated substrates. There is evidence that p62 can positively regulate Nrf2 by binding to its negative regulator, Keap1. However, there is also strong evidence that Nrf2 up-regulates p62 expression. Thereby, a regulatory loop is formed between two important signaling pathways, which may be an important target for drugs aimed at treating neurodegeneration. Constitutive activation of p62 in parallel with Nrf2 would most likely result in the activation of mTORC1-mediated signaling pathways that are associated with the development of malignant neoplasms. The purpose of this review is to describe the p62-Nrf2-p62 regulatory loop and to evaluate its role in the regulation of mitophagy under various physiological conditions.

Determining passenger traffic as important factor in urban public transport system

Abstract: Studies of passenger flows in planning the development of the large cities’ transportation system are of great importance. It is not possible to design an urban transportation network or improve the existing one without accurate and objective data obtained from field studies. The article describes a method for conducting a passenger traffic study.

Results of reliability evaluation of the 1921vk028 chip

Abstract: The article considers a model for evaluating the reliability of integrated circuits (IC) depending on the temperature of the crystal and the environment. The calculation and experimental prediction of the reliability of the 1921VK028 chips was carried out, the dependences of the minimum time to failure of the product on the temperature of the 1921VK028 IC crystal and the gamma-percent life of the IC on the ambient temperature were obtained. The obtained values of these chip parameters meet the requirements of ISO 11 0998-99

Cyclic Synthetic Peroxides Inhibit Growth of Entomopathogenic Fungus Ascosphaera apis without Toxic Effect on Bumblebees.

Abstract: In recent years, the number of pollinators in the world has significantly decreased. A possible reason for this is the toxic effects of agrochemicals reducing the immunity of insects that leads to their increased susceptibility to pathogens. Ascosphaera apis is a dangerous entomopathogenic fungus, afflicting both honeybees and bumblebees. We investigated fungicide activity of cyclic synthetic peroxides against A. apis isolated from Bombus terrestris L. The peroxides exhibited high mycelium growth inhibition of A. apis up to 94-100% at concentration 30 mg/L. EC50 values were determined for the most active peroxides. Two peroxides showed higher antifungal activity against A. apis than the commercial fungicide Triadimefon. The studied peroxides did not reduce the ability of bumblebees to fly and did not lead to the death of bumblebees. A new field of application for peroxides was disclosed.

Development of a new approach to diagnosis of the early fluorosis forms by means of FTIR and Raman microspectroscopy.

Abstract: This study is aimed at investigating the features of mineralization of the enamel apatite at initial stages of fluorosis development. Samples of teeth with intact and fluorotic enamel in an early stage of the disease development (Thylstrup–Fejerskov Index = 1–3) were studied by Raman scattering and FTIR using Infrared Microspectroscopy beamline at Australian Synchrotron equipment. Based on the data obtained by optical microspectroscopy and calculation of the coefficient R [A-type/B-type], which represents the ratio of carbonation fraction of CO32−, replacing phosphate or hydroxyl radicals in the enamel apatite lattice, the features of mineralization of enamel apatite in the initial stages of development of the pathology caused by an increased content of fluorine in the oral cavity were established. Statistical analysis of the data showed significant differences in the mean values of R [A-type/B-type] ratio between the control and experimental groups for surface layers (p < 0.01). The data obtained are potentially significant as benchmarks in the development of a new approach to preventive diagnostics of the development of initial and clinically unregistered stages of human teeth fluorosis, as well as personalized control of the use of fluoride-containing caries-preventive agents.

Results of reliability evaluation of the 1921vk035 chip

Abstract: The article considers a model for evaluating the reliability of integrated circuits (IC) depending on the temperature of the crystal and the environment. The calculation and experimental prediction of the reliability of the 1921VK035 chips was carried out, the dependences of the minimum time to failure of the product on the temperature of the 1921VK035 IC crystal and the gamma-percent life of the IC on the ambient temperature were obtained. The obtained values of these chip parameters meet the requirements of ISO 11 0998-99.

E-nose for the monitoring of plastics catalytic degradation through the released Volatile Organic Compounds (VOCs) detection

Abstract: The work presents the results of an artificial olfaction E-nose system application for detection of Volatile Organic Compounds (VOCs) – destruction products of OXO-biodegradable polyethylene films when exposed to Ultraviolet (UV) irradiation and heating. The E-nose system was based on eight piezoelectric quartz resonator sensors coated with polymeric sensing materials with various selectivity to analytes. The effect of prooxidants, materials based on variable valence metals, such as D2w, ferric stearate and ferric carboxylate, addition on polyethylene films (PE) photo destruction was studied. The dependence of the composition of VOCs mixtures emitted by PE films on the processing time, the power of the UV irradiation and on the nature of the modifying additive was established. In addition, the main emitted volatile compounds were identified and the dynamics of their formation for different catalysts during the plastics destruction were studied. The proposed E-nose system has proved to be an effective tool for assessing catalyst-prooxidants properties.

Synthesis, Docking, and In Vitro Anticoagulant Activity Assay of Hybrid Derivatives of Pyrrolo[3,2,1-ij]Quinolin-2(1H)-one as New Inhibitors of Factor Xa and Factor XIa

Abstract: Coagulation factor Xa and factor XIa are proven to be convenient and crucial protein targets for treatment for thrombotic disorders and thereby their inhibitors can serve as effective anticoagulant drugs. In the present work, we focused on the structure-activity relationships of derivatives of pyrrolo[3,2,1-ij]quinolin-2(1H)-one and an evaluation of their activity against factor Xa and factor XIa. For this, docking-guided synthesis of nine compounds based on pyrrolo[3,2,1-ij]quinolin-2(1H)-one was carried out. For the synthesis of new hybrid hydropyrrolo[3,2,1-ij]quinolin-2(1H)-one derivatives, we used convenient structural modification of both the tetrahydro- and dihydroquinoline moiety by varying the substituents at the C6,8,9 positions. In vitro testing revealed that four derivatives were able to inhibit both coagulation factors and three compounds were selective factor XIa inhibitors. An IC50 value of 3.68 μM for was found for the best factor Xa inhibitor and 2 μM for the best factor XIa inhibitor.

Influence of the polarization of a multielectron atom in a strong laser field on high-order harmonic generation

Abstract: We study the ionization and high-order harmonic generation (HHG) in argon by short linearly polarized laser pulses. We compare the populations of atomic orbitals and HHG spectra in a wide range of laser-pulse parameters, taking into account the dynamics of all orbitals based on the time-dependent density-functional theory (TDDFT) and only the most active orbital within the single-active electron (SAE) approximation. At high intensities of laser pulses, the atom polarization leads to suppression in the bound-state depletion due to the screening of the external field. The significant increase in the HHG yield is observed for the TDDFT calculations in comparison with the SAE calculations. The contribution of different orbitals in the TDDFT calculations of HHG spectra is discussed.

Attosecond-pulse metrology based on high-order harmonic generation

Abstract: An all-optical method to retrieve the temporal intensity profile of an extreme ultraviolet (XUV) attosecond pulse is proposed based on XUV-assisted high-order harmonic generation (HHG) by an intense infrared (IR) pulse. For a harmonic located on the XUV-induced high-energy plateau (beyond the IR HHG plateau), the measured harmonic yield as a function of the time delay between the XUV and IR pulses is shown to accurately map the temporal intensity profile of the XUV pulse. Single-color and two-color orthogonal, linearly polarized IR pulses are used to demonstrate the method.

Traffic simulation: an analytical review

Abstract: The constant increase in the number of cars in cities causes transportation problems that make it necessary to optimize the road network so as to satisfy the transport needs of the city. In this regard, modeling and optimal planning of the road network are of great importance. Motion modeling is a widely used method of traffic studies, modeling, planning and development of transport networks and systems. It represents the construction of a working model that reflects the similarity of properties or relations with the real problem under consideration. Modeling allows makes possible to study the complex tasks of traffic not in real conditions, but in the laboratory. In a more general sense, modeling can be defined as a dynamic display of some part of the real world by building a computer model and moving it in time. Simulation models of traffic aimed at modeling real transport operations can be divided into three categories: microscopic, macroscopic and mesoscopic modeling. These methods of modeling traffic flows are designed to solve the most common transport problems. In most cases, models allow determining such parameters as traffic intensity, average speed, delays and time loss. This study is an analysis of existing traffic flow simulations in terms of their functions, limitations, and application by various criteria.

Model of a Nonuniformly Heated Viscous Flowthrough a Bounded Domain

Abstract: A mathematical model describing the flow of a nonuniformly heated viscous fluid through a bounded domain under slip boundary conditions is studied. Sufficient conditions are derived for the solvability of the problem in the class of weak solutions. Energy equalities for the solutions are obtained. It is shown that the set of weak solutions is sequentially weakly closed.